Parallel imaging for NMR microscopy at 14.1 Tesla

Parallel imaging techniques using arrays of mutually decoupled coils have become standard on almost all clinical imaging systems. Such techniques also have great potential for high-field magnetic resonance (MR) microscopy, where measurement times are usually long and susceptibility artifacts can be severe. However, it is technically very challenging to design efficient high-frequency phased arrays for small-diameter, vertical-bore magnets, especially since standard decoupling methods, such as impedance mismatched preamplifiers, cannot be easily integrated. A four-coil phased array was constructed for microimaging at 600 MHz, and sensitivity encoding (SENSE) and generalized autocalibrating partially parallel acquisitions (GRAPPA) reconstructions of spin-echo and echo-planar images of the mouse brain were performed to reduce imaging time and susceptibility artifacts, respectively.